1. Field of the Invention
The present invention relates to a fluid mixing apparatus and a fluid mixing method, and more particularly to a fluid mixing apparatus and a fluid mixing method for distributing a fluid at a uniform flow rate in branch portions of a channel in the fluid mixing apparatus. More particularly, the present invention relates to a fluid mixing method for uniformly distributing a fluid to increase yields in a fluid mixing apparatus of numbering-up type including an increased number of units (referred to as microreactors) for precise chemical reactions or mixing.
2. Description of the Related Art
Micro space provides a large surface area per unit volume, allowing many reaction interfaces of reaction fluids to be formed and facilitating temperature control, which receives attention as a technique for increasing efficiency or velocity of reactions or mixing between fluids.
Generally, a microreactor that performs reactions or mixing while precisely controlling fluids in micro space has low throughput. Increasing the size of channels in the microreactor to increase the capacity and thus increase throughput, however, causes loss of basic functions (for example, of forming a laminar flow, or the like) specific to the microreactor. For this reason, various studies have been made on a numbering-up technique for increasing the number of channels.
In order to achieve precise chemical reactions in a microreactor, precise control of a flow rate is important. “Numbering-up of micro device: a first liquid-flow splitting unit (Chemical Engineering Journal 101 (2004) 421-429)” discloses an example in which a unit for splitting a liquid flow is provided upstream of a microreactor to split the liquid flow to the microreactor with tubes. With this method, however, variations in head pressure caused by placement of the tubes or variations in inner diameters of the tubes may cause flow resistance. Also, chips of sealing materials in connectors of the tubes may enter microchannels to block the channels. Bubbles of air trapped between the tubes and the connectors may cause variations in flow rate.
In order to achieve numbering-up more efficiently in a microreactor including a channel of a branch structure, reaction fluids need to be uniformly distributed to provide a uniform ratio of flow rates of the reaction fluids in each channel.
Japanese Patent Application Laid-Open No. 2004-243308 discloses a microchannel structure of numbering-up type, including a circularly recessed storage space for temporarily storing a fluid introduced halfway through a channel, and linear supply channels formed radially from the storage space. This proposes uniformly passing the fluid through each microchannel using the storage space as a buffer to prevent nonuniform pressure of the fluid.
Japanese Patent Application Laid-Open No. 10-267468 proposes a heat exchanger including, before distribution chambers, a main channel and distribution holes each having a diameter smaller than that of the main channel, thereby providing a pressure loss. Thus, a heat exchange fluid passes through the main channel and is distributed to the distribution chambers through the distribution holes, thereby allowing the fluid to uniformly flow into each distribution chamber and increasing heat exchange effectiveness.